Flame baffle for pulverized fuel furnaces



Oct. 17, 1933. w ,K SANDERS 1,930,566

FLAME BAFFLE -FOR PULVERIZED FUEL FURNACES original Filed'June e, 1931 *i* Q? *g v llaa.'

2 www ATTO/e afs Y -40 chamber of the furnace before it Patented Oct. 17, 1933 t ,UNITED-STATES PATENT OFFICE y'FLAME BAFFLE FoRPULvEmzED FUEL n Y FURNACEs,A

William K. Sanders, McGill,`Nev., assignor of one-half to Edward f, .City, vUtah Y e riginalqapplication JuneA 6, V1931, Serial N0.l f

542,600. Divided and this application July 28,' i932. vserial No. 625,431

J. `Franklin, Salt Lake.

2 Claims, (o1. 12221-235). f

This invention relates to an improved flame baiiie for pulverized fuel furnaces. The invention is particularly intended and adaptedv for use in connection withL pulver-ized fuel furnaces for 5 heating water tube boilers. f i

This application is a division of application Serial Number 542,600, filed by me on June 6, 1931.

The main object of the invention isto provide a means for preventing the name and entrained particles of unburned or partly burned fuel from passing directlyv into theV front Ior first pass of a water tube boiler whenfthe fuel burner or nozzle is located at or near the upper portion of a furl5'nace. `It has been found, in the operation of a furnace boiler and fuel burner combination such as above referred to that the draft pull maintained in the furnace has a tendencyy to divert the flame from 2o the burner directly into the first bank of boiler tubes over the top ofthe refractory bailling provided inthe bank of tubes, thus preventing the name from maintaining the U-'shaped trajectory which is deemed desirable. This diver- 2 5 sion, or shortening, of Vthe rflame trajectory causes 1 a considerable decreasein the length of time that the fuel remains in the furnace, and hence prevents the complete combustion of all particles of fuel vwhile in suspension in the combustion space of the furnace. The result is, that unburned or partly burned particles of fuel are drawn directly into the gas passages betweenthe'b'oiler tubes causing a large loss in fuel and consequent' clogging of the gaspassages by reason of these fuel particles congealing and adhering to the boiler tubes.

My invention provides means whereby this difiiculty is overcome and the flame from the burner is forced to pass downwardly into the combustion passes to the Water tube boiler.

Another object of my invention is torprovide means which will increase the radiant heat absorbent surface and also increase the evaporative eiect of the boiler.

Other objects of my invention will appear hereinafter.

The accompanying drawing illustrates embodiments of my invention and referring thereto:

Fig. l isa vertical section of one type of water tube boiler and furnace thereto showing my invention applied thereto.

Fig. 2 is a section on line 2 2 in Fig. 1.` Y

Fig. 3 is a partial section of a baffle tube and the refractory covering blocks therefor.

In Figs. 1 `and 2 my invention is illustrated Vas applied in. connection with .a boiler. and` furnace construction comprising a water tube boilergl, Aa combustionchamber 2, and a burnerB adapted y for' combustion of pulve'rized fuel `such ask coal dust or atomized, fuel oil; z The boiler is shown as comprising three banks'offw'ater tubes 4, 5 landl with bale walls 7, 8 and 9A attherear of each bank .of water tubes, ,saidbaffle walls being staggered so as to insure that the product of combustion 65 will pass in tortuous path and corne-into efecf tive contact with substantially.;` the .entire area' of each bank of water tubes,`.a connection being provided to flue 14 for conducting the combus-v tion gases after they have passed the last bank forsame. l

`The water tubes arey shown aslconnected. at their lower ends vto a water drum 10 and at" their upper ends to drums 11, 12 and 13, and suitable 75 pipingis provided for connecting theupper and 4lower headers so as'to-pr'ovideffor water circulaI tion. In ordinary practice the circulation is eff: fected by connections leading from the lower drum 10 to one of the upper drums or headers for the water tubes by pipes extending above the combustion chamber 2, leaving the space between the burner 3A` and the firstfbankof water. tubes substantially unobstructed. `With such' an arrangement, there isr a` tendencywfor the ames to pass from the burner directly 'to the passage 15above theiirst bafe wall 7 aforesaid instead of passing in the desired Ushaped course indicated by the arrows in Fig. 1.

YTo provide for deflection of the gases inthe 90 desired course I provide a baflle extending downwardly from the top of the combustion chamberl and comprising water tubes extending through the wall of the combustion chamber and connected for circulation'of water therethrough and ,Y refractory means covering said tubing so as to protect the same, the construction being such that all parts of such tubing within the combustion chamber are protected bysaid refractory covering from the heat of theburner. s

The furnace roof 16 extends over the combustion chamber 2 and is shown as being composed of refractory material through which projects the fuel burner 3 fed by coal pipe 1'7. Across the width of the furance is disposed' a 4plurality of bent tube elements 18 forming a baiiie screen. These tubes 18 extend downwardly-fromY an upper header 24` and are bent laterally at their lower portions so as to pass through the furnace side walls 19, terminating in the relatively ver- 70 of boiler tubes to a stack or otheroutlet means other convenient means. 'Illetubes25and head.-

ers 11, 12 and 13 may be covered in any convenient manner, as for instance; by heat-,r,esisting;V

material 26, forming a contihuaticnothe fur'- nace roof insulating covering 1 6. The tubes 18,

may be covered with blocks .27 oi any suil'ablema-` terial such as illustrated` Vi'nLlifg. 3'; to provide a surface relatively impervious to the passage of flames or fuel particles therethrough, and to di-` vert the flames downwardly from thezfuel burneror nozzle 3, into the U- shaped path previously described: fj Y d Inlthe operatibn of' the boilerfrelatively cool water*` from the lower or mudl drum' 10 of the boiler flowsthrough the piping 21F tothe-headers 20', thence through thev tubes^`18 and Z5-'to the boiler drum' 11. With` the described" constructionQthe flames fromA the burner 3 are prevented from taking the shorter pathabove referred to and are i'orced'to` pass rst downwardly and then upwardlybefore they passthrough the rst bank of' water' tubes; thereby' insuring that the fuel particles1wiil'remainj within-I the combustion chamber a` sufit'rcient` timey for-jeiective combustion. thereofand obviating the losses and difficulties' above referredv to; VThe deflection of the 'products'of combustion iirthis mannery also insuresthat they will be brought into mcreefffectiver contact with" thel first bankof water` tubes, thereby increasing thei evaporative effect. Adf- `diti'omtl evaptnati'vel effect is also secured by con- 'tact of'thehot products of combustion with the water tubesjl and' bythe heat absorbingfand radiating actionof the` baille' wall' mounted there- Iclaim: f j

` 1. A water tube boiler" and' furnacejconstruction comprising a combustion chamber provided withtopand'sidewalls and having an outlet passage at the upper portion of'said chamber', a water tube. boiler. arrangedv to receive gases passing'from said. outlet. passage', a burner adapted to direct llame: into the. upper part. of said? combustion chamber and a baille extending. downwardly from the top. of. the:- combustion. chamber. but leaving an unobstructed space between it and the bottom of the chamber so as to prevent passage of flame from the burner directly to the said outlet, and-tocause theflame to pass downwardly under saidl ballleand then upwardly to said outlet passage, said bale comprising header means at the top of the combustion chamber and communicati'ng with the upper part of the boiler, header .means at theside of the combustion chamber communicatingA with the lower part of the boiler, saidheader means-being outside the combustion cl1amber;water tubes extending downwardly from. the header means at the top of the combustion chamber and' having their lower ends bent'` laterally and communicating with the header means. .at the side of the combustion chamber so` as'to provide for circulation between the boiler andthe water tubes through said header means, the respective ends of each water tube.v extending through the top and side walls of the combustion' chamber to communicate with the respective aforesaid. headery means and' refractory baffle means mountedonsaid water tubes to protect the same from-,the heat ofthe flame.

in the? combustion.. chamber.

2. water vtube boiler -and furnace construction comprising a combustion chamber havingv an outlet passageat. the upper `portion thereof, a water. tube boiler arrangedv to receive gases passing from said outlet'passage, a burner adapted to direct flame lintothe upper part of said cham.- -berand-a baille' extending downwardly from. the top. of the combustion chamber so. as tov prevent passage of flame from said outlet passage, but leaving an unobstructed passage below ksaid-,baflle through. whichthe, flame -isdeflectedin passing to said outlet passage, said baffle comprising. water tubesand refractory baille the burner directly to the meansmountedon and coveringv said water tubes,

al header extending above. the combustion chamber. and.` in communication. with said water tubes .and withlthe upper partA of. water tube boiler, headers atthe respective. sides of the combustion chamber -and in communication-.with thelowerpartof the water tube boiler and` withthe water tubes in: the baille, said; water tubes inthe baille' extending' downwardly from 4said upper-header andn-bentlaterally at their lower portions and extending through theside walls of the combustion. chamber and communicating outside the combustion chamber with the respective headers at the sides. of. thefcombustionl chamber.

' K. SANDERS. 

